Unit 2: Community Ecology Flashcards
What is Community?
populations of different species (heterospecific) within an area and the interactions among them
What is a Direct interaction?
species interact directly, such as mutualisms, predatation, etc.
What is Indirect interaction?
species interact through one or more intermediary species
How are types of interactions categorized?
by their effects on fitness
What is Amensalism’s effect on fitness?
neutral-negative (e.g. elephant “stomps” on bug)
What is Commensalism’s effect on fitness?
positive-neutral (e.g. birds eats the insects cows kick up by accident)
What is Intraspecific?
same species (e.g. population ecology)
Is population ecology density-dependent or density-independent in terms of logistic growth?
density-dependent
What is Interspecific?
different species; relating to how the species rely on the same resources (e.g. community ecology)
There is a general ______ correlation between niche overlap and competition intensity
positive (*on a graph, it is a positive slope)
What is Niche?
range of resources used and conditions tolerated
What is Fundamental Niche?
theoretical range of environment conditions that a species can tolerate (max & min)
What is Realized Niche?
portion of the fundamental niche that is actually occupied/the resources actually used in nature (given limiting factors)
Can the Realized Niche be bigger than the Fundamental Niche?
No, the realized niche is small because it’s in competition with other species in nature
What happens when two species in a community have overlapping niches?
This will only happen if species are equal.
1. Competitive Exclusion Principle
2. Niche Differentiation
3. Resource Partitioning
What is Competitive Exclusion Principle?
no 2 species within a habitat can coexist when they compete for the same resources at the same place and time
- one species outcompetes the other (asymmetric competition)
- local extinction of weaker competitor
In competition exclusion, the fitness is ____ where the two species’s fundamental niche overlap
low, only the superior species can get the niche overlapping in fundamental niche because natural selection selects against individuals that compete
What is Resources Partitioning?
change in resource use caused by competition over generations
What is Niche Differentiation?
when 2 species separate out of the niche space in which they overlap
What is Character Displacement?
evolutionary changes in traits that make niche differentiation possible (e.g. change in body size)
When does character displacement occur?
happens when species are sympatric with a competitor, therefore the species will have different body types because they’re in competition
What is Sympatric?
overlapping in an area
What is Allopatric?
in separate areas (geographically)
When species are allopatric, this means they are not in ________, and the species will have very similar body sizes.
competition
What is Mimicry?
when one species resembles another
What is Bayesian Mimicry?
when a harmless/patable species mimics a dangerous/unpalatable species
Who is the Bayesian Mimicry names after?
Henry Walter Bates (Wallace’s companion in Brazil)
What is Müllerian Mimicry?
2 or more harmful species mimic each other
Who discovered müllerian mimicry?
Fritz Müller
What is Emsleyan (Mertensian) Mimicry?
type of mimicry where a harmful (deadly) species resembles a less harmful one
How do predators protect the Emsleyan/Mertensian Mimicry?
predators develop learned avoidance of the less harmful model, in order to protect the deadly mimic
What is Aggressive Mimicry?
when a predator mimics a desirable species (e.g. venus fly trap-pretty flower)
What is Herbivory’s effect on fitness?
positive-negative
What is Predation’s effect on fitness?
positive-negative
What are the types of Prey adaptations to raise fitness?
- camouflage
- escape behavior (“startle behavior”)
- toxins (aposematic coloration)
- schooling/flocking (patterning)
- mechanical defense (shells, thorns, scales)
What is Aposematic Coloration?
warning coloration used as a defensive mechanism against predation, which memorable for predators
What are the types of Predator adaptations?
- strength
- stalking
- heightened senses
- speed
- chemicals
- surprise
- cooperation
What is Co-Evolution?
when 2 interacting species reciprocally influences each others adaptation overtime, which is an Co-Evolutionary Arms Race for prey
What is Parasitism’s effect on fitness?
positive-negative
Can parasites controls the host?
yes, they control the host to benefit themselves
What is Obligate Brood Parasites?
group of birds that reproduce only by laying eggs in the nest of other species
What is Mutualism’s effect on fitness?
positive-positive
When does mutualism occur?
occurs over long periods of time in which the species grow dependent on each other
What is Mutualism?
symbiotic relationship where both species benefit
What are the 3 categories of mutualism?
- resource-resource
- resource-service
- service-service
Who is Judith Bronstein?
explains mutualism as “reciprocally exploitative interactions” and provides net benefits to both partner species
What is Nectar Robbing?
feeding on nectar without pollination
